What is the meaning of the compiler warning "Ambiguous reference: GETLIST"?

 GETLIST is an array variable that is created by CA-Clipper, by
 default, as the list of all currently used GET objects.  (The
 @...GET command preprocesses into an AADD (Getlist, ...) call,
 and READ references Getlist also.)

 If you don't declare GETLIST in your code the compiler won't
 realize that the variable will in fact exist at runtime, hence
 the warning.  If this bothers you, you can put the statement
 MEMVAR GETLIST in a header file that is shared throughout the
 application, or even declare GETLIST as a LOCAL in functions that
 use GETs and READs if your program organization allows it.